Black Max Wind Direction Indicator. Black Max is a versatile, high performance wind direction indicator that attaches quickly to the mast or boom. The tough, high impact plastic vane is designed to withstand years of punishment and the abuse of small boat sailing. The stainless steel mounting arm and set screw, as well as a tough plastic mounting base, add to the system's durability. Wind vane length is 8" (20 cm). Black Max is packaged in its own unbreakable storage sleeve for safe keeping when not in use.